Screw-driver.



UNITED STATES Patented June 9, 1903.

PATENT OEEIc LAROY S. STARRE TT, OF ATHOL, MASSACHUSETTS,ASSIGNQRI.TO.T.HE L. S. STARRETT COMPANY, OF ATI-IOL, MASSACHUSETTS, ACORPORATION OF MASSACHUSETTS.

SCREWEDRIVER.

sPEcmIcATroN forming part of Letters Patent No. 73o,so4, dated June 9, 1903. Application filed October 31,1901. Serial No. 80,620. (No model.)

To (tZZ whom, it may concern: Be it known that I, LAROY S. STARRETT, ofAthol, in the county of Worcester and State of Massachusetts, haveinvented certain new and useful Improvements in Screw-Drivers, of whichthe following is a specification.

This invention consists, primarily, of a screw-driver provided with anadjustable pair of inherently elastic fingers suitably compressed andadapted to hold the head of the screw about to be inserted in firmcontact with the tip of the screw-driver shank and by a rearwardmovement of the com- ,uressing device to release the screw when detired.These fingers are of tempered sheet metal and preferably formed integralwith a sliding sleeve which so rrounds the tool-shank, such sleevehaving an internal bushing provided with a yielding friction deviceadapted 1o normally hold the sleeve and fingers at any point desired.The sleeve will be externally milled or inclosed by a milled thimbleriveted to it and its bushing. A sliding clasp or ring surrounding thefingers forces them inwardly to engage the screw or releases them whenthe movement is reversed. A stop projecting from the shank engages thesleeve, preventing it from moving too far, and a like stop on one fingernear its tip tends to prevent loss of the sliding ring.

I prefer to make the tool-shank tubular'at its free end-that is, with aterminal socket and locking device into which may be insertedsuccessively tool-tips having stems of uniform diameter, each engagingthe locking device,and dissimilar outer ends with slightlyvaryinglengths adapted to fit materially different sizes of screws or tools toform holes for inserting them. The elastic fingers and the clasp-holdthe screw-head against the point ofthe removable tool-tips in operativeposition, the fingers having inwardly-extending ends concaved to fit thescrew held on drill-stem shoulder, so that considerable force may beapplied and the screw or drill held firmly and withdrawn when required.The fingers cling to the beveled under side of the screw=head and holdthe tip engaged in the slot of the screw, and since the projecting stopalways checks the advance of the fingers at a given point, whilescrew-heads vary in thickness with their size, I make the tips forsmall-sized screws slightly longer than those designed for large screws,because the latter have thicker heads. For brad-awls and twistdrills tomake holes for inserting screws the stem of the perforating-tool is anenlarged axial prolongation, an exact duplicate of the stem of theexchangeable screw-driver tips. The elastic fingers seize the tool bythe shoulder where it is joined to said prolongation.

In the drawings, Figure l is a side view of one of my improvedscrew-drivers, showing in full lines the screw held against the shanktipby the elastic fingers and movable ring, dotted lines indicating theposition of fingers when the ring is moved rearwardly without moving thesleeve. Fig. 2 shows, on an enlarged scale, the sleeve, fingers, andring applied to a tool-shank with tubular terminal socket and aremovable tip, the tip-stem and locking device being indicated by dottedlines. Figs. 3, 4, and 5 are sectional views of the sleeve, fingers, andring. Fig. 6 shows the socketed shank with fingers and ring holding atwist-drill having an enlarged stem engaging the socket and lockingdevice indicated in Fig. 2. Fig. 7 is a transverse section taken on line7 7 of Fig. 6. Fig. 8 is a side view of two of the removable tips ofdifferent lengths.

10 represents the tool-handle, 11 the shank or body of the tool, and 12the operative tip which engages in the slot or nick in the screw-head,as shown in Fig. 1. The tips 12 may be continuous and integral with theshank, as in Fig. 1, or the shank may be made with a socket at its outerend and provided with a suitable locking device, so that tips of variousforms may be inserted therein, as indicated in Figs. 2, 6, and 7.

13 is a metallic sleeve surrounding the toolshank and provided with twoor more elastic fingers l4, projecting forward on opposite sides of theshank. Figs. 3, 4, and 5 show a tubular bushing or lining 15, securedWithin sleeve 13 and formed with a suitable friction-tongue 16, pressinginwardly against the'shank to hold the fingers in any adjustedposition.A stop-pin17,projectingslightly from the shank, limits the forwardmovement of the sleeve and fingers at the proper point.

3 and 4.

18 is a sliding ring surrounding the fingers and movable lengthwise ofthem.

The fingers 14 have terminal inward extensions 19, with concave faces tofit upon the beveled under surface of the head of the screw, which isthereby drawn backward and held firmly against the tool-tip. The fingersare made thin near their junction with sleeve 13 and normally springoutwardly near their free ends. I/Vhen it is desired to insert a screw20, its nicked head is applied to the tip 2, while the fingers arespread and advanced, as in dotted lines, Fig. 1. Then the ring 18 ismoved forward, drawing the fingers inwardly until their inwardextensions 19 engage the head of the screw, as seen in full lines inFig. 1.

When not required for use in holding the screw or drill, the sleeve andfingers are moved back from the tip, as shown in Fig. 2 and in dottedlines in Fig. 6. At such times the removable tip will be held in theshanksocket frictionally, preferably by a slender tongue 21, integralwith the socket-wall, as in Fig. 2, pressing inwardly against thetipstem. 1

Fig. 6 illustrates a special adaptation of my invention. The twist-drill22 has an enlarged stem 12 just fitting the terminal socket of the shank11 and engaging the lockingpiece 23 therein. The spring-fingers 14 bytheir terminal extensions 19 seize and hold the drill by its shoulderedenlargement, as in Fig. 1 they are seen to hold the screw 20 by itshead. Both are held with great firmness. When a hole has been bored, thefingers serve to withdraw the drill from it. The drill is then removedfrom the shank, and a tip, as in Fig.

'2, substituted, and the screw held thereto, as

illustrated in Fig. 1-.

In constructing my new screw-driverattachment I propose to strike up thefingers and sleeve from a piece of sheet metal, form the sleeve, shapeand temper the fingers, then applya milled thimble 24 around the sleeve,and bya single rivet unite the thimble, sleeve, and bushing, the thimblebeingindicated in Figs.

I am aware that rigid screw-holding fingers pivoted on a sliding collarcompressed by an inclosing tube or ring and each furuishetl with aspring riveted in place and interposed between it and the tool-shankhave heretofore been applied to screw-d rivers. Such devicesI disclaim.Myimprovement dispenses with hinges, rigid fingers, auxiliary springs,

slightly-varying lengths, as stated, to compensate for the difference inthickness of screw-heads for which they are respectively adapted.

I claim as my invention- -1. A screw-holding attachment for screwdriverscomprising a sleeve having integral spring-fingers with inward terminalextensions, in combination with a bushing fitting within said sleeve andadapted to fit closely to the screw-driver shank, and having anintegral, inwardly-struck-out spring-tongue, causing sufficient frictionon said shank to maintain'said attachment where placed on said shank,substantially as set forth.

2. In a screw-driver, the handle and the shank having a tubular terminalsocket and a plurality of detachable tips of uniform diameter fittingand suitably locked 'therein, such tips being severally adapted forscrews'of different sizes and made of slightly-varying lengths, tocompensate for the'differen'ce in thickness of screw-heads, incombination with .a sliding sleeve having'a plurality of screwholdingfingers with beveled inner faces, a compressing and releasing device forthe fingers, and a positive stop limiting the forward movement of thesleeve and fingers, substantially as set forth.

3. In a screw-driver, the handle, the shank :having a fixed projectingstop, a tubular terminal socket, and detachabletips suitably se curedtherein, such tips being'adapted, terminally, for difierent-sized scres, and those for small screws being slightly longer than thosefittingthe large sizes, in combination with a sliding sleeve formed withelastic fingers having inward terminal extensions with beveled innerfaces, and with a bushing and friction device within suchsleeve 'to'holdthe Isleeve and fingers in their retracted or advanced position,substantially'as set forth.

In testimony whereof I have affixed my signature in presence of twowitnesses.

LAROY s. STARRET Witnesses:

FRANK E. WING, WILLARD G. NIMs.

in Letters Patent No. 730,804.

c o 2.: o as S- o O It is hereby certified that in Letters Patent No.780,804, granted J one 9, 1903, upon S. Starrett, ofAtholf'M-assachusetts, for an improvement in the application of Laroyerror appears in the printed specification requiring correction, as heldon f should read head or; and that the Screw-D rivers, an

follows: In line 43, page 1, the words I said Letters Patent should beread with this correction therein that the same may conform to therecord of the case in the Patent Ofiice.

Signed and sealed this 30th day of June, A. D., 1903.

E. B. MOORE,

[SEAL] Acting Commissioner of Patents.

